Motor vehicle seat back

ABSTRACT

A vehicle seat back comprises firstly a rigid frame having first and second side uprights and top and bottom cross-members interconnecting the first and second side uprights, and secondly a resilient supporting sheet fixed to the rigid frame and placed so as to come directly into contact with the back of a user. The supporting sheet forms a bag that is fitted onto the rigid frame over its first side upright so as to cover the top and bottom cross-members and the first side upright, the resilient supporting sheet being fixed to the second side upright.

FIELD OF THE INVENTION

The present invention relates to motor vehicle seat backs.

More particularly, the invention relates to a motor vehicle seat backwhich comprises firstly a rigid frame having first and second sideuprights and top and bottom cross-members interconnecting the first andsecond side uprights, and secondly a resilient supporting sheet fixed tothe rigid frame and placed so as to come directly into contact with theback of a user.

BACKGROUND OF THE INVENTION

In this type of back, the side uprights and the top and bottomcross-members forming the rigid frame are constituted by tubes, and theresilient supporting sheet is fixed directly to the inner periphery ofthe frame. The supporting sheet is therefore substantially in the formof a rectangle and all around its outer periphery it has fasteners forcooperating with complementary members, correspondingly disposed allaround the inner periphery of the rigid frame. It will therefore beunderstood that fitting the supporting sheet to the frame requires thefasteners of said sheet to be fastened one after another to thecomplementary members of the rigid frame, thereby complicating assemblyof the back and considerably increasing the time and cost of assembly.

SUMMARY OF THE INVENTION

An object of the present invention is to mitigate the above-mentioneddrawbacks.

The invention achieves its object by the fact that the supporting sheethas a front face and a rear face, each having respective top and bottomedges and respective first and second side edges, said front and rearfaces being secured to each other firstly via their top and bottomedges, and secondly via the first side edges so that the supportingsheet forms a bag for fitting onto the rigid frame by passing over thefirst side upright and covering the top and bottom cross-members and thefirst side upright, and by the fact that the second side edges of thefront and rear faces of the resilient supporting sheet are fixed to thesecond side upright.

By means of these dispositions, the resilient supporting sheet whichforms a bag can be fitted directly onto the rigid frame via one of itsside uprights, and then needs to be fixed only to the other sideupright, thereby making it possible to simplify assembly of the seatback for fitting to a seat proper of a vehicle seat, and considerablyreducing the time required for said assembly.

In preferred embodiments of the invention, use may optionally be made ofone or more of the following dispositions:

the second side upright is constituted by a side plate of depth, asmeasured perpendicularly to the front face of the resilient supportingsheet, greater than the depth of the first side upright and of the topand bottom cross-members;

the first side upright and the top and bottom cross-members are madefrom a single piece of tube that is substantially U-shaped;

the side plate has a rear edge and a front edge for facing the back ofthe user, said front edge being substantially identical in shape to thefirst side upright;

the side plate has an outside face facing away from the first sideupright, the outside face having first and second series of hooks, andthe second side edges of the front and rear faces of the resilientsupporting sheet having respective first and second series of hemsreceiving respective first and second rigid rods which are fixed to thefirst and second series of hooks by the resilient return force exertedby the front and rear faces of the resilient supporting sheet;

the side plate has a top end and a bottom end relatively welded to thetop cross-members and to the bottom cross-members; and

the side plate is covered by a protective cover-plate.

BRIEF DESCRIPTION OF THE DRAWINGS

Other characteristics and advantages of the invention appear from thefollowing description of an embodiment thereof, given by way ofnon-limitative example and with reference to the accompanying drawings,in which:

FIG. 1 is a perspective view of the vehicle seat back of the invention;

FIG. 2 is a perspective view of a rigid strength member for a seatproper to which the back of the invention is to be connected;

FIG. 3 is a perspective view of the rigid frame of the back; and

FIG. 4 is a plan view in section of the back.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In the various figures, the same references are used to designateelements that are identical or similar.

FIG. 1 shows a back 1 for a front seat of a motor vehicle, which backcomprises a rigid frame 2 and a resilient supporting sheet 3 fixeddirectly onto the rigid frame 2 of the back.

The frame 2 comprises a first side upright 41, a second side upright 5,and top and bottom cross-members 42 and 43. The first side upright 41and the top and bottom cross-members 42 and 43 are constituted by tubesthat can be welded together or they can be made by bending a singlepiece 4 of tube.

The side tube 41 and the top and bottom tubes 42 and 43 are circular insection and of small diameter, e.g. about 3 centimeters (cm).

The ends of the top and bottom tubes 42 and 43, remote from the sidetube 41, are fixed to the side plate 5 which extends substantiallyvertically between a top end 51 and a bottom end 52.

The side plate 5 also comprises an inside face 53 placed facing the sidetube 41 and an outside face 54 facing away from said side tube 41. Theseinside and outside faces 53 and 54 of the side plate 5 are defined by arear edge 56 and a front edge 55 that is intended to face the back of auser occupying the seat.

As can be seen in FIG. 3, the ends of the top and bottom tubes 42 and 43of the frame 4 which are connected to the side plate 5 can be flattenedby stamping prior to being fixed to the top and bottom ends 51 and 52 ofsaid side plate 5 by welding.

The resilient supporting sheet 3 of the back is substantially in theform of a bag comprising a rear face 7 and a front face 6 that isdesigned to come directly into contact with the back of a user sittingon the seat. In order to provide the seat user with sufficient comfort,the supporting sheet is constituted by a resilient net of relativelynarrow mesh, or by a resilient fabric.

The front and rear faces 6 and 7 of the resilient sheet have respectivetop edges 62, 72 and bottom edges 63, 73, and also respective first sideedges 61, 71 and second side edges 64, 74.

In order to enable the resilient supporting sheet to form a bag whichcan be fitted directly onto the rigid frame 2 of the back, the front andrear faces 6 and 7 are connected together, firstly along their top andbottom edges 62, 72 and 63, 73, and secondly along their first sideedges 61, 71. The front and rear faces 6 and 7 can be interconnected bystitching, or they can be made as a single piece.

Thus, once the resilient supporting sheet 3 is fitted onto the frame 2by surrounding the top and bottom tubes 42 and 43 and the side tube 41,all that remains to be done is to fix the second side edges 64 and 74 ofthe front and rear faces of the sheet to the side plate 5.

For this purpose, the second side edges 64 and 74 of the front and rearfaces 6 and 7 of the sheet comprise relatively a first series of hems 20and a second series of hems 21 with first and second rigid rods 22 and23 engaged respectively therein.

The various hems 20 and 21 of the first and second series need to bespaced apart from one another sufficiently to enable the rigid rods 22and 23 to present portions that are uncovered.

The side plate 5 has a first series of hooks 25 and a second series ofhooks 26 on its outside face 54, which hooks are situated respectivelyin the vicinity of the front edge 55 and of the rear edge 56 of saidside plate.

Thus, in order to fix the resilient supporting sheet to the side plate5, it suffices to stretch the front and rear faces 6 and 7 of said sheetso as to bring the hems 20 and 21 over the outside face of the sideplate, and then to place the uncovered portions of the rigid rods 22 and23 so as to bear respectively against the first and second series ofhooks 25 and 26. The supporting sheet is then held in place on the rigidframe 2 by the resilient return force exerted by the front and rearfaces 6 and 7 of said sheet on the hooks of the side plate 5.

The outside face 54 of the side plate 5 is then covered by a removablecover-plate 17 which is fixed directly to said side plate, e.g. bysnap-fastening or by screw fasteners.

As can be seen in FIG. 4, according to an advantageous characteristic ofthe invention, the side plate is of depth e₁ considerably greater thanthe depth e₂ of the side tube 41 measured in a direction perpendicularto the front face 6 of the supporting sheet 3, i.e. in a direction Xwhich extends between the front and rear edges 55 and 56 of the sideplate 5.

The depth e₁ of the side plate 5 can vary between its top and bottomends 51 and 52 while nevertheless remaining considerably greater thanthe depth of the tubes forming the frame 4. By way of example, the sideplate 5 can be substantially triangular in shape with a bottom end 52 ofdepth greater than the depth of its top end 51, the front and rear edges55 and 56 then converging toward end 51.

Thus, as can be seen in FIG. 1, the depth of the side plates in thedirection X perpendicular to the supporting sheet 3 is sufficient toenable devices involved in user safety or comfort to be fitted directlyto the outside face 54 of said side plate.

In particular, the outside face 54 of the side plate can be provided atits top end 51 with a winder 8 for a seatbelt 9, or more generally witha top anchor point for said seatbelt 9. Two bottom anchor points (notshown) for the seatbelt can be fixed, for example to the seat proper 10of the vehicle seat (FIG. 2), or more precisely to the two side plates11 and 12 of the seat proper 10 of the seat.

Thus, in the event of the vehicle being subjected to a longitudinalimpact tending to throw the user of the seat forwards, the top portionof the seatbelt 9 pulls essentially on the side plate 5 of the back,which is strong enough to withstand this pull because of its relativelylarge depth in the X axis direction, i.e. in the direction of thelongitudinal axis of the vehicle.

The outside face 54 of the side plate 5 can also be provided with anairbag device 13 in its middle portion, halfway between its top andbottom ends 51 and 52, the airbag serving to provide additional lateralsafety for the seat user.

Similarly, the outside face 54 of the side plate can also be providedwith a hinge mechanism 14 at its bottom end 52, the hinge mechanismbeing for connection to the seat proper 10 of the seat to enable theback 1 to pivot about a horizontal axis Y extending substantiallyparallel to the front face 6 of the resilient supporting sheet 3.

In one possible embodiment of the connection between the back 1 and theseat proper 10, the rigid frame 2 of the back is placed between the sideplates 11 and 12 of the seat proper 10 so that a pivot 15 situated atthe bottom end of the side tube 41 is received in a hole 12 a of theside plate 12 of the seat proper, while the hinge mechanism 14 issituated directly in a suitable housing formed on the inside face of theside plate 11 of the seat proper. The two side plates 11 and 12 of theseat proper are connected to each other by means of two spacers 18 and19.

The hinge mechanism 14 is controlled by a handle 16 fitted to thecover-plate 17 covering the outside face 54 of the side plate 5, saidhandle 16 being connected to the hinge mechanism 14 by means of a rigidconnecting bar (not shown) passing through a hole 11 a formed in theside plate 11 of the seat proper 10.

The cover-plate 17 also has an orifice 17 a through which the seatbelt 9passes, and an additional cover-plate 17 b for separating from the maincover-plate when the airbag is deployed.

As can be seen in FIGS. 1 and 3, the front edge 55 of the side plate 5and the side tube 41 of the frame 4 are substantially identical in shapeso as to provide symmetrical side supports for a user of the vehicleseat.

Advantageously, the front edge 55 of the side plate 5, the cover-plate17, and the side tube 41 all present respective substantially convexportions facing forwards so as to provide lumbar support for the user ofthe seat.

What is claimed is:
 1. A motor vehicle seat back comprising firstly arigid frame having first and second side uprights and top and bottomcross-members interconnecting the first and second side uprights, andsecondly a resilient supporting sheet fixed to the rigid frame andplaced so as to come directly into contact with the back of a user,wherein the supporting sheet has a front face and a rear face, eachhaving respective top and bottom edges and respective first and secondside edges, said front and rear faces being secured to each otherfirstly via their top and bottom edges, and secondly via the first sideedges so that the supporting sheet forms a bag for fitting onto therigid frame by passing over the first side upright and covering the topand bottom cross-members and the first side upright, and wherein thesecond side edges of the front and rear faces of the resilientsupporting sheet are fixed to the second side upright.
 2. A backaccording to claim 1, wherein the second side upright is constituted bya side plate of depth, as measured perpendicularly to the front face ofthe resilient supporting sheet, greater than the depth of the first sideupright and of the top and bottom cross-members.
 3. A back according toclaim 2, wherein an inflatable airbag device is fitted to the sideplate.
 4. A back according to claim 2, wherein a winder device for aseatbelt is fitted to the side plate.
 5. A back according to claim 2,wherein the side plate includes a hinge device for connection to a seatproper of a vehicle seat to enable the back to pivot about a horizontalaxis.
 6. A back according to claim 1, wherein the first side upright andthe top and bottom cross-members are made from a single piece of tubethat is substantially U-shaped.
 7. A back according to claim 2, whereinthe side plate has a rear edge and a front edge for facing the back ofthe user, said front edge being substantially identical in shape to thefirst side upright.
 8. A back according to claim 2, wherein the sideplate has an outside face facing away from the first side upright, theoutside face having first and second series of hooks, and the secondside edges of the front and rear faces of the resilient supporting sheethaving respective first and second series of hems receiving respectivefirst and second rigid rods which are fixed to the first and secondseries of hooks by the resilient return force exerted by the front andrear faces of the resilient supporting sheet.
 9. A back according toclaim 2, wherein the side plate has a top end and a bottom endrespectively welded to the top cross-member and to the bottomcross-member.
 10. A back according to claim 2, wherein the side plate iscovered by a protective cover-plate.